An assay is needed for the diagnosis of bladder cancer that is sensitive, accurate and suitable for screening high risk populations. Current diagnostic methods involve patient risk and discomfort, are unsuitable for detection of low grade neoplasms or lack specificity. Our previous work suggests that there are tumor-associated antigens (TAA) in the urine of bladder cancer patients and that detection of these antigens in urine has potential for diagnosis of bladder cancer, even low grade bladder neoplasms. Although one of these antigens is also found in urine of patients with urinary tract infections, other antigens appear to be more specific to bladder cancer. We propose to continue the biochemical isolation and characterization of these antigens to prepare specific antisera. These antisera will be used to continue the development of an enzyme-linked immunoassay (microELISA), suitable for use in a clinical laboratory. They will also be applied to a study of exfoliated tumor cells in urine by immunofluorescence. Finally, we will quantitate these antigens in the urine of bladder cancer patients and suitable control populations and perform an extended, multi-hospital study to determine the usefulness of our assay in the detection of bladder cancer.